Over the years, cant strips have been used by roofers, particularly by roofers applying built-up membrane systems of tar paper and asphalt, to provide a gentler angle for the membranes to follow when transitioning from a roof deck to a parapet wall, a skylight curb and the like. Typically, such cant strips have been made of wood or a wood fiber material and have had triangular shaped cross sections thereby providing a 45 degree angle instead of the 90 degree angle in the absence of such a cant strip. The goal has been to reduce the severity of any right angle turn by the membranes so that the membranes, which become brittle with age, do not crack and create leaks. A further reason for such cant strips is that the membrane material does not have much structural strength and requires solid support for the transition from the horizontal decking surface to the vertical wall surface.
Despite the use of such cant strips, problems remain. First, these triangular cross sectioned cant strips still create a stressful angle for the membranes to follow as the transition from the horizontal roofing deck to the triangular cross sectioned cant strip still requires a transition angle of 45 degrees and this often is too much angle for the roofing membrane to handle over time. In particular, asphalt membranes still have a tendency to crack and split at the 45 degree angle between the horizontal decking surface and the cant strip surface. Second, as the cant strip is made of wood or wood fiber material, they can absorb water and decompose if small cracks in the membrane go undetected and water penetrates to the cant strip surface. The cant strip can hold this moisture and subsequently promote dry rot of wood decking, sheathing or structural members.
Application of the current cant strips typically involves fastening by a mechanical means such as nailing. Further, to go around or inside corner sections upon a roof, cuts at the ends of the cant strips, usually 45 degree cuts must be made. All of this cutting and nailing adds to the installation time and hence, to the cost of the roofing job.
It is an object of the present invention to provide a cant strip capable of reducing the strain on the roofing membrane as it transitions from a horizontal surface to a vertical surface.
It is a further object of the present invention to provide a cant strip system having a preformed shape, especially ends, such that cutting and trimming expenses can be reduced.
Still another object of the present invention is to provide a cant strip suitable for application without nailing or other mechanical means.
A still further object of the invention is to provide a cant strip composed of a material resistant to degradation by moisture.